messingr@Kodak.COM (Rich Messinger x24361 B83, Rm 528, RL, 02221) (08/21/90)
Gentlepeople, I have a question about if it is feasable to do this and how to do it? I currently have a set of cisco routers routing thru an X.25 cloud using internal company circuits. I have a new location that wants to join the network but they would rather use a Sun system that they have to do the routing on their end. What kinds of problems can I expect to see if any? Is there any better or worse software on the Sun end of things? We have the current cisco's serial interface as plain X25 encapsulation. Any help will be appreciated. Richard Messinger Eastman Kodak
satz@cisco.com (Greg Satz) (08/21/90)
>> I have a question about if it is feasable to do this and how to do it? >> >> I currently have a set of cisco routers routing thru an X.25 cloud >> using internal company circuits. I have a new location that wants >> to join the network but they would rather use a Sun system that >> they have to do the routing on their end. >> What kinds of problems can I expect to see if any? >> Is there any better or worse software on the Sun end of things? >> We have the current cisco's serial interface as plain X25 encapsulation. The cisco X.25 software can be setup to forward X.25 calls based on destination (called) X.121 address. However it sounds like you just want the Sun to participate in the IP over X.25 routing you already have setup. This should work just fine for the IP over X.25 communication. You will need to have the Sun forward the routes it knows about to the other cisco routers on your X.25 backbone. If you are using RIP then this is simple. If you are running IGRP you can either use static routes or redistribute RIP into IGRP and back for that one Sun. Greg
mussar@bcars53.uucp (G. Mussar) (08/21/90)
I've have connected Suns running the Sunlink x25manager software to Ciscos through X.25 packet networks. It works just fine (so far). I don't have enough equipment (ie. Suns) to network them together and the use one as a gateway router to the X.25 network/Cisco, but, it is quite feasible. -- ------------------------------------------------------------------------------- Gary Mussar |Bitnet: mussar@bnr.ca | Phone: (613) 763-4937 BNR Ltd. | UUCP: ..uunet!bnrgate!bcars53!mussar | FAX: (613) 763-2626
satz@cisco.com (Greg Satz) (08/21/90)
>> We ran into a problem when we tried this a year or two ago. There is a >> philosophy difference between cisco and Sun on how IP routing over X.25 >> should be done. cisco routers like to treat an X.25 network as a >> single multi-point network, where each router has a list of X.121 >> addresses corresponding to the IP addresses for each other router, and >> will build circuits on demand and close them after an inactivity >> timeout expires. (This is similar to the way DDN X.25 operates, I >> believe.) This is basically true. If you do not time out your connections on the DDN, the PSNs (packet switch nodes) will do it for you to reclaim resources. However I believe they will only do this for DDN Standard which are IP over X.25 calls. >> Sun's X.25 over IP implementation, however, likes to treat the X.25 >> network as a collection of permanent point-to-point links, each with >> its own network or subnet number. It also insists that one end of >> each link be responsible for ensuring that the circuit is up at all >> times. Provided you do not pay connect time, this is a fine model. Can Sun handle multiple VCs using the same IP subnet/network number? Or must they be different? >> We did get the Sun to talk to the cisco router, but we had these problems: >> >> 1) Since the cisco assumed that each router on the X.25 network >> was directly connected to each other one, it refused to route an >> IP packet back over the same X.25 interface it came in on. We relaxed this restriction in the 8.0 release when we introduced the concept of routing neighbors for all routing protocols, including IGRP and RIP. You do something like: router igrp 666 network 10.0.0.0 neighbor 10.0.0.1 neighbor 10.0.0.2 This will cause the router to send a direct routing update to hosts 10.0.0.1 and 10.0.0.2. Routing updates will still be broadcast too. The routing code is also smart enough to do split horizon on the neighbor instead of on the interface. This has the benefit of allowing packets to be sent out over the same interface they were received without sending a redirect. Routes learned by neighbors on the same interface will be sent to the other neighbors on that same interface (but not back to the neighbor who spoke of them originally). This gives you the flexibility to have it both ways. Treat the X.25 network like a big LAN with the assumption that all routers hear one device's routing updates. Or like a collection of point-to-point lines where you hand-craft your own routing topology using the neighbor subcommand. >> 2) The cisco liked to build parallel X.25 circuits to the same destination. >> Sun's x25manager barfed at this. I think there might have been a way to >> disable this on the cisco, but I'm not sure. The x25 nvc N configuration command will control this. By default N is 1 which should help Sun's software interoperate with ours. >> 3) The Sun had to take the responsiblity for keeping the circuit up, >> since it doesn't do circuit building on demand. We considered having a mode where the circuits come up immediately. However I have never heard anyone ask for this so I didn't bother. There are plenty of things to do based on what is asked for. Greg Satz cisco
feldman@spiff.Tymnet.COM (Steve Feldman) (08/23/90)
We ran into a problem when we tried this a year or two ago. There is a philosophy difference between cisco and Sun on how IP routing over X.25 should be done. cisco routers like to treat an X.25 network as a single multi-point network, where each router has a list of X.121 addresses corresponding to the IP addresses for each other router, and will build circuits on demand and close them after an inactivity timeout expires. (This is similar to the way DDN X.25 operates, I believe.) Sun's X.25 over IP implementation, however, likes to treat the X.25 network as a collection of permanent point-to-point links, each with its own network or subnet number. It also insists that one end of each link be responsible for ensuring that the circuit is up at all times. We did get the Sun to talk to the cisco router, but we had these problems: 1) Since the cisco assumed that each router on the X.25 network was directly connected to each other one, it refused to route an IP packet back over the same X.25 interface it came in on. 2) The cisco liked to build parallel X.25 circuits to the same destination. Sun's x25manager barfed at this. I think there might have been a way to disable this on the cisco, but I'm not sure. 3) The Sun had to take the responsiblity for keeping the circuit up, since it doesn't do circuit building on demand. We did these experiments over a year ago, so perhaps cisco has changed their implementation to get around these problems. I'm pretty sure that Sun hasn't done anything about it. Steve Feldman BT Tymnet, Inc. feldman@Tymnet.COM
smart@mel.dit.csiro.au (Robert Smart) (08/24/90)
In article <25073@boulder.Colorado.EDU> feldman@spiff.Tymnet.COM (Steve Feldman) writes: >We ran into a problem when we tried this a year or two ago. There is a >philosophy difference between cisco and Sun on how IP routing over X.25 >should be done. There is a freeware implementation of IP over X.25 for Suns. It was written by Julian Onions (jpo@cs.nott.ac.uk) Computer Science Department Nottingham University Nottingham, NG7 2RD ENGLAND It certainly addresses many of the problems, and you get the source if you want to do more. Given the unwillingness of the UK to hook up to the Internet he may not be in a position to make it available for anonymous ftp [there is an IP/ftp to CB/ftp and/or ftam gateway somewhere and it would be interesting to know if that extends to anonymous access and if so how it works]. Anyway if anyone is interested and Julian Onions authorizes it I will be happy to make the version I have available for anonymous ftp. Bob Smart <smart@mel.dit.csiro.au>
dave@ecrc.de (Dave Morton) (08/29/90)
I think most of Europe (at least Germany at any rate) use the tunnel software from Julian instead of that from Sun. Dave Morton, European Computer Industry Research Centre Tel. + (49) 89-92699-139 Arabellastr 17, 8000 Munich 81. West Germany. Fax. + (49) 89-92699-170 E-mail USA: dave%ecrc.de@pyramid.com EUROPE: dave@ecrc.de
dupont@inria.inria.fr (Francis Dupont) (09/02/90)
In article <989@ecrc.de>, dave@ecrc.de (Dave Morton) writes: > I think most of Europe (at least Germany at any rate) > use the tunnel software from Julian instead of that from Sun. Now Sun France provides a new IP over X.25 for SunLink 6.0. The virtual circuit management program is named "x25mgr" (not "x25manager") and supports : * static virtual circuits carrying IP traffic (same than old "x25manager") * dynamic virtual circuits carrying IP traffic (new, hardly needed in France for Transpac, in place of "tunnel software"). * dynamic virtual circuits carrying IP traffic over DDN network * dynamic virtual circuits carrying OSI/CLNP traffic over X.25 For dynamic VC, the interface is not a Point-To-Point interface and routing implications are well described in docs. Shutdown after idle time is provided for dynamic VC, etc ... This is a big improvement of old "x25manager" software. Sun France gives it to all sites with SunLink (SunNet ?) X.25 6.0 licence, but I believe it is available in USA. Francis.Dupont@inria.fr